


What's Mine is Yours

by AlienApparatus, hhopp, manifestingwings



Category: Supernatural
Genre: Angst, Bickering, Canon Divergence, Castiel Has Self-Esteem Issues, Castiel Has a Crush on Dean Winchester, Dean Has Self-Esteem Issues, Dean Winchester Has a Crush on Castiel, Fluff, Love Confessions, M/M, Memories, Pining, Possession, Sarcasm, Sharing a Body, Spoilers, They love each other anyway, s12 Finale
Language: English
Status: Completed
Published: 2017-07-19
Updated: 2017-07-19
Packaged: 2018-12-04 08:05:35
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,207
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11551014
Author URL: https://archiveofourown.org/users/AlienApparatus/pseuds/AlienApparatus, https://archiveofourown.org/users/hhopp/pseuds/hhopp, https://archiveofourown.org/users/manifestingwings/pseuds/manifestingwings
Summary: An angel needs consent to enter a new vessel. Seeing as Cas is one of the most important people in his life, Dean doesn't mind saying Yes to save the guy's life. Of course, when you're possessed by an angel, that means they have access to all those pesky little thoughts inside your head-- especially the ones you've been trying to keep hidden all these years.





	What's Mine is Yours

**Author's Note:**

> So last night a few of us in the group chat for the DCBB (which is coming along nicely, might I add) decided to write something round-robin style. We all wanted to explore what might happen if Cas smoked out of his vessel and joined Dean in his before Lucifer could get him-- thus, this was born. It took a few hours and it was 2AM before we finished, but it was a lot of fun and we're all kinda proud of it.

Dean sees Lucifer come up behind Cas.  His mind races and he tries to open his mouth to warn him.  A thought hits him. An idea. He has to act quickly, though. He prays for a miracle for good measure. 

 

"Cas, man, get out of there. Smoke out!” Cas narrows his eyes at Dean in that infuriatingly cute way he does and Dean screams, “Yes!"

 

Cas's eyes go wide for a fleeting moment before his body suddenly lurches. His head is thrown back and the icy blue wisps of disembodied angel burst from his open mouth.  Dean understands, suddenly, what Jimmy said years ago about being chained to a comet. It's so staggering that he doesn't notice Mom shoving past him, towards Lucifer.  His entire body lights up, as if someone took a sparkler to each and every nerve ending. It feels like his insides are replaced with cold water and his mind is suddenly not his own.

 

In the wild shit storm going on in his head he can distantly hear Sam shouting. A fight has broken out.. His eyes move toward the scene before him, but not entirely of his own accord. Mary throws punch after punch at Lucifer. Sam is shouting... at him?

 

“Dean!"

 

Dean is on his knees by Cas' corpse, Cas' body, but Cas is alive, Cas is... 

 

Cas is a warm presence at the back of his mind, not a comet but a softly burning fire, calming Dean throughout. It's Cas. It's just Cas. He looks up at his brother, blinking. He thinks he is in control of his body, but he can't really be sure. “Sammy?"

 

Oh, thank God. He might actually have to send a fruit basket into the void for this one. Cas gives him enough control to be able to move his head and talk. Sam's eyes widen as he realizes what happened, and is trying to get a question out when Dean's tongue starts moving of it's own accord. Or rather, Cas’.

 

"Dean is fine.” Cas speaks softly through Dean as he stares at Sam, eyes full of sympathy. "We both are. Your brother saved my life.” Dean feels a wave of affection flow through him. He knows it isn't his own, but it’s all for him. Cas turns their gaze to the portal, now disappeared with Lucifer and Mary nowhere to be seen. Dean feels a double stab of panic, one from him and one from Cas. Mom. Mom is trapped in that other world with **Satan**. Cas brings them to their feet. "Your mother," is all he says to Sam.

 

It’s a good thing Cas is able to hold him up because the shock would be holding Dean to the floor like a magnet otherwise. Sam nods solemnly. 

 

_Dean, are you alright?_ It’s Cas' voice, Cas normal voice, not the one coming out of Dean's own mouth, but echoing around his head like a PA system.

 

_Oh, peachy._ Dean's sarcasm punches through his anxiety and he can’t help it. But Cas's overwhelming concern washes over him then so clearly he isn’t fooled. _Mom's... damn it._

 

"Sam," Cas says suddenly, his concern shifting to new panic. "Sam, the baby, the nephilim." Sam nods and dashes off into the house.

 

Sam is gone and Dean doesn’t know what to do. Inside the confines of his own head, he slumps. _What the hell do we do next?_ Even in the form of a thought— or perhaps more so because he can’t hide behind his voice— his hopelessness leaks through. Something warm starts to glow inside his ribcage, and it makes it a little better. Cas' voice echoes around the inside of his skull again. 

 

_We'll find a way to fix this, Dean._

 

Dean has never felt comfort like this. Something that actually comes from a place within himself. It spreads through his body, a calm, cooling feeling washing over every nerve and easing his mind. It isn't really himself, he knows that, but it’s real and good and for once in his life he doesn’t feel like arguing. For once, he can believe everything will be okay.

 

While it’s kind of freeing, not having to express his thoughts and emotions out loud, Dean realizes that the more time Cas spends kicking around inside his head is more that Cas could find— Dean's memories, his thoughts. Most of it he doesn’t mind Cas knowing, but...

 

_Cas? What about your meatsuit?_

 

Vessels. Temporary housing. That’s easy to deal with, and he knows that as that thought runs through his head Cas is able to see it. _We can take it with us. I'll see what I can do back at the bunker. If it's irreparable then I'll simply find something else._

 

A part of him is saddened, at that. He's gotten so used to seeing Cas, all tall and dark haired and eyes like you'd see on a ring in some thousand dollar jewelry store. He'll certainly miss it if that has to end.  _We'll fix you up, Cas. What would we do without this handsome mug?_ Dean has to mentally slap himself at the sincerity of that comment and cram down a sudden onslaught of thoughts that are definitely not appropriate right now.

 

Cas is silent maybe just a little too long before he speaks again. _Like I said, I'll see what I can do._

 

Dean turns— or maybe it's Cas— when Sam comes barreling out of the house, sans baby. Cas is confused; Dean prepares for the worst. "So, uh," Sam starts. "Kid's gone. Also, not a kid. He's, like, twenty."

 

_Figures._ Cas laughs at that, somewhere where he's not freaking out because there's a super-charged nephilim on the loose.  It's an interesting sensation, Cas' mirth mixing with both of their panic. He resolves to make that happen at least a few more times while they're roommates in this very limited space. "Did he seem... you know. Like he's plotting to destroy the universe?" Dean asks. Sam rolls his eyes.

 

“Well, he's a galactic-level superpower with no moral compass. And he’s on the loose, in a world full of monsters, trigger-happy hunters, and, you know, the rest of humanity,” comes Sam's exasperated reply. "So I think we could stand to be at least mildly concerned. He didn't say a word to me either. To be honest, I'm not even sure he can.” Dean can feel Cas' exasperated sigh throughout his entire being, but he can only laugh mentally. Cas speaks with his voice. 

 

"We'll figure it out. For now, we should return to the bunker and see if I can get out of your brother." Dean tries not to see that as an innuendo, but he does, which means Cas does, too, which means Cas somehow manages to shoot a mental glare at him. He really should have considered what he was signing up for.

 

But then, maybe Dean hadn't thought this through either. His head was filled with—

 

_No, no, no, stop, do not pass go, do not collect 200 dollars. No. Not going there._

 

_Not going where?_

 

Dean fills his head with every kind of alarm he can think of, sirens and Metallica and dogs barking until he can get to another train of thought— e.g., moving Jimmy Novak's corpse to the Impala.

 

_Dean._ Cas... is he whining? _No, I'm not whining. Please stop, those noises are obnoxious._

 

Sam speaks up. "So, uh, I'm glad that you're alive and all, Cas, but it's weird hearing you coming out of my brother." Dean-- this is definitely all him, because Cas starts glaring again-- arches an eyebrow. ”Or... you know what I mean. Can you, like, deepen your voice or something so I know it's you?”

 

"Sam, you're the one making this weird for everyone now"

 

_Dean_. Cas's tone is slightly reprimanding

 

_What? He is!_ Dean feels Cas's huff of annoyance before he takes over again.

 

"Is this more acceptable?" Dean's vocals have taken on a deeper, more weirdly gravelly tone and Sam face just kind of screws up into a pained, almost tortured look.

 

"Let's uh..." Sam clears his throat awkwardly. "Let's get your body out of here, come on.”

 

_Dude, you're gonna fuck up my vocal cords_ , Dean complains. _How the hell do you talk like that?_

 

_I find Jimmy Novak's voice to be very annoying. And puny. Your voice is already deep enough that I wouldn't mind using it, but I don't want to make Sam uncomfortable._

 

Sam walks over to Cas' body and picks it up gingerly. There's blood all over. It makes Dean feel sick, but Cas simply presses against his consciousness reassuringly. 

 

_You look so tiny. Like a doll._

 

_I do not know what you mean by that._

 

Somewhere in the back of his mind, Dean thinks about how normally Cas is so... vast. Angelic. To see his normal body devoid of that power, doing its best Raggedy Andy impression, it's shocking. He doesn't know how to articulate that into one complete thought, but Cas seems to get the gist. The warm and fuzzies start up again. _Dude, how are you doing that?_

 

_Just a bit of grace. You seem stressed._ And that's actually... kind of touching. But he can't get used to that, because Cas isn't always around to drug him up on angel mojo just because something has gone wrong. In this life, something's always going wrong.

 

As Sam heads towards the impala, Dean turns to look one last time at the place where their mother had disappeared into the glowing tear in reality only moments ago, dragging Lucifer along with her. She has to be okay. They will find her, they will bring her home, and they will all be a family again. All four of them.

 

Another rush of Cas's warm appreciation. How is Dean supposed to keep his thoughts and emotions in check when Cas insists on feeling so damn much? He didn't know Cas **could** feel this damn much.

 

“Hey, can somebody get the car door?" Sam grumps from across the yard.

 

Dean tries to move his right leg forward at the same time Cas tries to move his left. This does not end well for anyone but Sam, who thinks it’s just the funniest thing in the world. Dean and Cas both direct a glare at him. 

 

_Okay, we really just need to pick one person to hold the reins._

 

_How do you propose we compromise on that?_

 

_Well, it's my body, for one thing, and for another, I saved your ass. I’m driving._ Another exasperated sigh is all the agreement Dean's going to get as he drags his own body up and walks over to Sam to open the back door to the Impala. 

 

"Wait," Cas blurts, doing that weird thing with Dean's voice again. "Sam, you should stay here and see if there is anything to learn from this location. And... Kelly.” Dean feels the wave of sadness at that, and tries just mentally reaching out for Cas. It seems to work to some degree, but Cas is still sad. "Dean and I will go home and see what we can do about our, um, predicament.”

 

Sam agrees and walks off. The two (one?) of them get into the driver's seat. 

 

_Can I learn how to drive?_ Cas asks. Dean goes about as white as a sheet. 

 

_I don't know that that's such a good idea right now, man. Too much going on._

 

Cas grumbles something in his mind, but he's apparently much better at disguising it than Dean is. Maybe it's an angel thing. Some silence lapses before Cas sighs. _Can we talk about the things that you're trying and failing not to think about?_

 

_What things?_ he asks, trying to keep his cool. He absolutely knows what things Cas is talking about, but hell if he isn't going to make it difficult to have this conversation.

 

_Dean,_ Cas's voice is soft. Imploring. _Listen. What you're doing to yourself... I can feel the toll it takes on you._ Dean's breath hitches then as the weight of Cas's emotions crash through him. _You hide so much of yourself from everyone._ Cas calms, then, and his comforting presence nudges at Dean's consciousness. Dean wants to fight back but how... how can he? How is he supposed to fight this? 

 

_Cas, don’t—_

 

_I already know._

 

Dean may have stopped breathing entirely now, he's really not sure.

 

_I don't know what you're talking about._ Dean puts all the gruffness he can muster into those seven words, but he knows it won't fool Cas. It never had, even when they were two separate minds.

 

_Dean_ , Cas reprimands, and he doesn't even need to put it into words at this point, it's just a wave of feeling. Sadness, exasperation, pining. Pining for Dean, and years of quiet, patient love.

 

Dean definitely isn’t breathing at this point, which would be a bigger deal if it weren't for Cas hanging around. They can make a straight, no-stops trip home, which is good, considering there was a corpse in the back seat. Dean remembers this and blasts the A/C. He doesn’t feel the change in temperature. 

 

He takes a mental breath, really more of a moment to steady himself. _Cas, I don’t— is this really the time for this conversation? We've kind of got a lot on our plate._

 

_We've always got a lot on our plate, Dean. I've been waiting years to have this conversation. Please don't run away from me, not now._

 

Well, great. Now he feels like an ass.

 

_Cas, you know I'm not..._ he flounders. Surely Cas can take his pick of the various suggestions floating to the top of his mind: important. Good enough. Good with relationships. Good for you. His chest starts warming up again. _Dammit, would you stop doing that?_

 

_I'm sorry, Dean._ He's quiet. Then, it's as if the thought wall Cas has put up comes down. Dean can hear every thought, see every memory. There's him, patching up a kid who was almost werewolf-chow. Leaving to meet with Amara when the universe was about to collapse. Showing Cas how to shave and brush his teeth after he fell. There are words, too. 'I wish you saw yourself the way I see you' and 'You're more important to me than you'll ever know' and 'I love you.'

 

_Cas..._

 

_Dean, you have made mistakes. And I know that you don't think you're good enough or whatever other excuses you've made, but allow me to tell you that I think you're plenty good enough. Not perfect, that goes against the rules, but perfect for me._

 

Dean's hands wring the steering wheel in a white-knuckle grip as Cas speaks to him, says these things he would never, ever allow himself to believe if he couldn't actually right this second feel every little thing the stupid angel was saying as if each syllable is being burned into his very soul.

 

"Cas... Damn it." his eyes burn and his voice breaks as he suddenly, unintentionally speaks aloud.

 

_You set me free, Dean_. Cas soothes with his voice and his grace. _You have forgiven me far more times than I feel I deserve, you've saved my life... and you've given me a family._ Dean feels a tear fall he didn't realize was there. He takes in a shaky breath but says nothing more so Cas speaks again. _Why would you do all of that? Can you think of no reason?_

 

If Cas wants to attack him in his own brain like this, then fine. Two could play at that game. He knows that Cas is just as self-deprecating as he is, so fine. He calls to mind his own memories, memories of Cas risking his life to get Dean to Sam to stop the apocalypse, Cas frowning when he didn't get a joke, Cas interrogating a cat with the same level of intensity he would give to a seasoned criminal, the gummy grin on his face when he announced he was going to be a hunter.

 

_Can I think of a reason? Yeah, actually, I can, Cas, because you deserve it. You deserve a whole lot more, actually, but it's all I can give you._

 

Cas is silent for a moment. _Dean, you've given me far more than I deserve._

 

_You're a hypocrite, you know that?_

 

_Am I?_ Cas doesn’t need to articulate what they both remember, then— Cas, standing in a ring of holy fire, sucking in all those Leviathans, going with Metatron, saying yes to Lucifer. It’s a completely silent battle of 'Who's The Worst' neither of them are willing to concede. Dean makes Cas recall that one time he started the entire apocalypse, and then the other one, and also the time he was a demon. Cas whips out the fact that if it weren't for him, his mother would be safe and sound, and that is what breaks Dean. 

 

_I guess we both just kinda suck, huh?_

 

_That's my point. But I love you anyway. And there is no reason to pretend you don't feel the same. I am literally inside your brain, Dean, but I know you. You're not subtle._

 

He's tempted to snipe back, get Cas riled up into an argument again, but Cas shoots him the equivalent of a side-eye glance and he decides against it. Out loud, he sighs. _I..._ He can't get the words out. It's just three little words, not that hard, but for the life of him he cannot put them together, even within the safety of his own head. 

 

_I know, Dean. You don't have to say it._ There's no resignation there, and somehow that bolsters him. 

 

_No. I’m— you should get to hear it too, Cas. Castiel. I— damn it. I love you._

 

His own elation at finally saying it out loud, and knowing Cas reciprocates, and... and... well, it mixes with Cas' side of things too and he starts feeling all buzzy and light inside, like summertime. It's probably not the best idea to be driving like this, to be honest, even if there are no other cars on the road. Oh, how he wishes he could kiss Cas right now. 

 

_Can you pull over? I may be able to heal my old vessel with grace alone._

 

_Yeah, uh... yeah._ He puts the car in park on the green bank of grass side of the road and lets Cas take over his limbs. The sheer energy coursing through his fingertips as they're run over the gaping hole in his best friend's (more than best friend, now) old body feels weird. In a good way, though. The damage knits itself together and the blood is cleared away; it almost looks like regular old Cas is just sleeping in the backseat. 

 

_I'm about to evacuate, alright?_ Dean nods and Cas smokes out, leaving Dean feeling hollow in a way he hadn't an hour ago. Bluish white light tangles through the air before concentrating outside Jimmy Novak's pink, soft-looking lips, finally passing through them. Cas sits up and wastes no time in tangling his hand in the hair at the base of Dean's neck, drawing him in for a kiss eight years in the making.

**Author's Note:**

> (Small apology for those couple uses of bold. It's kind of annoying to read but italics had to be reserved for when they were thinking back and forth.)
> 
> We own nothing. Kudos, Comments, you know the drill if you've ever read an author's note before.


End file.
